In situ multi-phase sensing for 3d printing

Abstract

In various aspects, 3D printers, and sensor systems coupled to or integrated with the 3D printers are disclosed. The sensor systems may include image and second sensors for detecting potential defects or print artifacts. During printing, an energy beam source forms a weld pool by melting selected regions of print material, which solidifies to produce the build piece. The image sensor may image an area including the weld pool to determine a landing location of matter ejected during the heating of print material to form the weld pool. The second sensor may detect a defect in the build piece based on the determination of the landing location. Print operation may be suspended while the sensor data is used to repair the defect, after which 3D printing resumes. In this way, for example, high quality build pieces can be produced with reduced post-processing times, and hence a higher manufacturing throughput.

What is claimed is: 
     
         1 . A sensor system for a three-dimensional (3D) printer, comprising:
 a first sensor configured to determine a landing location of matter ejected during heating of print material to form a weld pool, wherein the weld pool defines a portion of a build piece once the weld pool hardens; and   a second sensor configured to detect a defect in the build piece based on the determination of the landing location.   
     
     
         2 . The sensor system of  claim 1 , wherein the second sensor comprises an eddy current sensor. 
     
     
         3 . The sensor system of  claim 2 , wherein the defect comprises at least an inclusion, a subsurface void, a region of partially sintered print material, or a region of unsintered print material. 
     
     
         4 . The sensor system of  claim 1 , wherein the first sensor comprises a camera. 
     
     
         5 . The sensor system of  claim 4 , wherein the first sensor comprises a first camera adjacent a second camera, such that the first camera is oriented relative to the second camera to obtain a three-dimensional representation of a trajectory of the matter. 
     
     
         6 . The sensor system of  claim 1 , wherein the second sensor is coupled with a recoater of the 3D printer, such that the second sensor is configured to move with the recoater. 
     
     
         7 . The sensor system of  claim 1 , further comprising at least one processor configured to receive information from at least the first sensor or the second sensor. 
     
     
         8 . The sensor system of  claim 7 , wherein the received information includes images of the matter. 
     
     
         9 . The sensor system of  claim 7 , wherein the at least one processor is further configured to modify printing of the build piece based on the received information. 
     
     
         10 . The sensor system of  claim 9 , wherein modifying the printing of the build piece includes modifying the printing at or near the landing location. 
     
     
         11 . The sensor system of  claim 10 , wherein fused powder material is located at the landing location, and modifying the printing at or near the landing location includes instructing the 3D printer to re-melt the fused powder material. 
     
     
         12 . The sensor system of  claim 9 , wherein modifying the printing of the build piece includes modifying the printing to include printing into the build piece a conduit from the landing location to an external surface of the build piece. 
     
     
         13 . The sensor system of  claim 9 , wherein modifying the printing of the build piece includes suspending printing. 
     
     
         14 . The sensor system of  claim 13 , wherein the at least one processor is further configured to instruct the 3D printer to remove the matter using at least a vacuum, a brush, a scraper, a machining tool, or a chemical agent. 
     
     
         15 . The sensor system of  claim 7 , wherein the at least one processor is further configured to determine whether the received information meets a criterion for suspending printing to perform a repair. 
     
     
         16 . The sensor system of  claim 15 , wherein the at least one processor is further configured to instruct the 3D printer to refill a void in the build piece created by the repair prior to resuming the printing of the build piece. 
     
     
         17 . The sensor system of  claim 7 , wherein the at least one processor is further configured to determine, based on the received information, at least a trajectory, a velocity, a size, or a material composition of the matter. 
     
     
         18 . The sensor system of  claim 1 , wherein the matter includes a ceramic compound or an intermetallic alloy. 
     
     
         19 . The sensor system of  claim 1 , wherein, when the print material is magnetic or paramagnetic, the second sensor is configured to adjust a magnetic field to expel the matter from the landing location. 
     
     
         20 . The sensor system of  claim 19 , wherein after expelling the matter, the second sensor is configured to adjust an intensity of the magnetic field to excite the print material in the landing location sufficiently to refill a void left by the expelled matter. 
     
     
         21 . A three-dimensional (3D) printer, comprising:
 a build plate;   a recoater configured to successively deposit layers of print material onto the build plate;   an energy beam source configured to form a weld pool by heating selected regions of the print material in each layer to form a build piece;   an image sensor configured to image an area including the weld pool to determine a landing location of matter ejected during the heating of the print material to form the weld pool; and   a non-optical sensor configured to detect a defect in the build piece based on the determination of the landing location.   
     
     
         22 . The 3D printer of  claim 21 , wherein the non-optical sensor comprises an eddy current sensor. 
     
     
         23 . The 3D printer of  claim 21 , wherein the defect comprises at least an inclusion, a subsurface void, a region of partially sintered print material, or a region of unsintered print material. 
     
     
         24 . The 3D printer of  claim 21 , wherein the image sensor comprises a camera. 
     
     
         25 . The 3D printer of  claim 21 , wherein the image sensor comprises a first camera adjacent a second camera and oriented relative to the second camera to obtain a three-dimensional representation of a trajectory of the matter. 
     
     
         26 . The 3D printer of  claim 21 , wherein the non-optical sensor is coupled with the recoater and is configured to move with the recoater. 
     
     
         27 . The 3D printer of  claim 21 , further comprising at least one processor configured to receive information from at least the image sensor or the non-optical sensor. 
     
     
         28 . The 3D printer of  claim 27 , wherein the received information includes images of the matter. 
     
     
         29 . The 3D printer of  claim 27 , wherein the at least one processor is further configured to modify printing of the build piece based on the received information. 
     
     
         30 . The 3D printer of  claim 29 , wherein the at least one processor is further configured to modify the printing at or near the landing location. 
     
     
         31 . The 3D printer of  claim 30 , wherein fused powder material is located at the landing location, and the at least one processor is further configured to instruct the 3D printer to re-melt the fused powder material. 
     
     
         32 . The 3D printer of  claim 29 , wherein the at least one processor is further configured to modify the printing to include printing into the build piece a conduit from the landing location to an external surface of the build piece. 
     
     
         33 . The 3D printer of  claim 29 , wherein modifying the printing of the build piece includes suspending printing. 
     
     
         34 . The 3D printer of  claim 33 , wherein the at least one processor is further configured to instruct the 3D printer to remove the matter using at least a vacuum, a brush, a scraper, a machining tool, or a chemical agent. 
     
     
         35 . The 3D printer of  claim 27 , wherein the at least one processor is further configured to determine whether the received information meets a criterion for suspending printing to perform a repair. 
     
     
         36 . The 3D printer of  claim 35 , wherein the at least one processor is further configured to instruct the recoater or a re-filler element arranged with the 3D printer to refill a void in the build piece created by the repair prior to resuming the printing of the build piece. 
     
     
         37 . The 3D printer of  claim 27 , wherein the at least one processor is further configured to determine, based on the received information, at least a trajectory, a velocity, a size, or a material composition of the matter. 
     
     
         38 . The 3D printer of  claim 21 , wherein the matter includes a ceramic compound or an intermetallic alloy. 
     
     
         39 . The 3D printer of  claim 21 , wherein, when the print material is magnetic or paramagnetic, and the non-optical sensor is configured to adjust a magnetic field to expel the matter from the landing location. 
     
     
         40 . The 3D printer of  claim 39 , wherein after expelling the matter, the non-optical sensor is configured to adjust an intensity of the magnetic field to excite the print material in the landing location sufficiently to refill a void left by the expelled matter. 
     
     
         41 . A method for 3D printing a build piece, comprising:
 depositing a layer of print material;   heating a portion the print material in the layer with an energy beam to form a weld pool;   sensing first information with a first sensor;   determining, based on the first information, a landing location of matter ejected during the heating of the print material to form the weld pool;   sensing second information based on the landing location; and   detecting, based on the second information, a defect in the build piece based on the determination of the landing location.   
     
     
         42 . The method of  claim 41 , wherein the second sensor comprises an eddy current sensor. 
     
     
         43 . The method of  claim 41 , wherein the first sensor comprises first and second cameras. 
     
     
         44 . The method of  claim 43 , further comprising orienting the first camera adjacent the second camera, wherein the first information includes a three-dimensional representation of a trajectory of the matter. 
     
     
         45 . The method of  claim 41 , further comprising moving the second sensor upon moving a recoater of the 3D printer, wherein the second sensor is coupled with the recoater. 
     
     
         46 . The method of  claim 41 , further comprising receiving, by at least one processor from at least the second information. 
     
     
         47 . The method of  claim 46 , wherein receiving the second information includes receiving images of the matter. 
     
     
         48 . The method of  claim 46 , further comprising modifying printing of the build piece based on the second information. 
     
     
         49 . The method of  claim 46 , further comprising modifying the printing at or near the landing location based on the second information. 
     
     
         50 . The method of  claim 49 , wherein modifying the printing at or near the landing location includes instructing the 3D printer to re-melt fused powder material. 
     
     
         51 . The method of  claim 48 , wherein modifying the printing of the build piece includes modifying the printing to include printing into the build piece a conduit from the landing location to an external surface of the build piece. 
     
     
         52 . The method of  claim 48 , wherein modifying the printing of the build piece includes suspending printing.